October
17, 2004
Cumbres de Monterrey, Nuevo Leon, Mexico
OK it’s Sunday the 17th--last weekend--and we were camped in an
area in the Cumbres of Monterrey called Cienegas de Gonzales. We got a
little bit of a late start but we were looking for roosts around 9:30--the
sun takes awhile to get up over the canyon walls. So we found a few roosts.
Some of them were just brilliant. [The butterflies] were hanging from
Spanish moss and they just filled the mosses with bright colors.

We walked
around for a little while, still looking for roosts, not seeing too many
migrants. Seeing some migrants but not too many. But by 11 o’clock--between
11 and 12 o’clock--they were passing overhead by the millions.

"Seeing a million butterflies passing over is kind of magical,"
said Calvert.Photos
courtesy of Jonathan Dueck. (Click to enlarge.)

Millions
of butterflies were up there kettling. You would focus your binoculars
on near ones, on those in a kettle, and you’d keep changing the
focus toward infinity and more butterflies would appear, higher and higher
in the sky. It was just absolutely phenomenal. They
continued just pouring over until about 1 o’clock and then they
began to thin noticeably. And then we left that area, the Cienegas de
Gonzales.

I’ve
been along the route of the migration maybe 15 times, and I’ve seen
some pretty spectacular stuff, but I think this is the most butterflies
I’ve ever seen in migration over a particular area. I mean, this
compares in density to what you see in early Nov at the butterfly colonies
when they’re just arriving. The densities were just stupendous,
they were just absolutely astounding. Seeing a million butterflies passing
over is kind of magical.